Lmc
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[edit] Important science points.
Here is the draft to the paper.FirstLMCpaper
1) Radiation field is from starlight scattered by dust.
2) Bright UV is near bright stars.
3) Also dark areas in LMC. Why, when there is so much light and dust.
4) What is foreground extinction to LMC (in our Galaxy)?
Ans : For LMC 0.07 to 0.17 mag. Is there a map of the extinction?
5) How far is the LMC and what is the scale? How many pc is the FUSE aperture?
Ans: 50kpc & If the distance is 50 kpc then fuse aperture is 30" = 7 pc.
6) WISP data show a correlation with HI in the north but not the south. What about our data?
Ans: for our data it is not correlating at all.I broke the data into north and south and studied the correlation still it is not corrrelating.
Where is NGC 1818 where there is no dust and therefore no scattering? So there are no FUSE points near NGC 1818? 7) 15 locations(11 independent locations)are in N11. i) locations 3,4,20 (table:2 ) are very very high in UV beacause these three locations are present in OB association LH10 which is rich in early O stars. ii) 7,8,9,21 are located far away from any of the OB associations LH9,LH10, LH13 & LH14 where thare is no nearby early stars , hence very low UV intensity & sit below our correlation line.
[edit] from the plots
- We have studied the far ultraviolet(FUV)diffuse radiation in the large magellanic cloud (LMC) based on the observations in multi wavelenth regions like Ultraviolet and Infrared.
- we have primarily concentrated on the correlation studies of the FUV flux that is measured using the data obtained from both the Far Ultraviolet Spetroscopic Explorer(FUSE) mission for different targets and Ultraviolet Imaging Telescope (UIT)observations with that of Infrared flux in different bands obtained from Infrared Astronomical Satellite(IRAS).
- Then we have studied correlation of FUV diffuse radiation with total hydrogen column density which is calculated using a foreground reddening of E(B-V) from Schlegel et al.(1998) and gas to dust ratio of 2.22*10^22Hcm^-2 for LMC from Draine(2003)& got a fine correlation between the two upto an optical depth of almost 5 .
- We have also compared the FUV flux of both FUSE and UIT data for the same locations.
- In the plots IR vs UV we found two ponts with high IR intensity and total hydrogen column density.These two points are well inside the 30 Doradus which is an immense star forming region in LMC having an interacting complex of massive stars,molecular clouds,photoionised HII filaments and diffuse gases.Gas and dust clouds in 30 Doradus have been sculpted into elongated shapes by powerful winds and ultraviolet radiation from these hot clusters of stars.
- Hyland et al (1992),Rubio et al(1998)have shown many bright IR sources in 30 Doradus.The excess in IR in our two observed location in 30 Doradus may be due to some intrinsic IR sources or some heavily reddened early O stars.
- High total hydrogen column desity in those locations may be due to the presence of dense molecular clouds.
- Excluding those two points ,we observe a nice correlation between diffuse UV background intensity and IR intensity.
- Starline from N11 & LH15 associations(A.Cole,1999) are the strongest contributor to the scattered UV light component of the LMC .We found 15 locations(fig:1.2) from our data present in N11 region.
- From figure 2.1 to figure2.5 ,we saw in all those plots our correlation is decreasing beacause of seven points which are high in UV.
Out of those seven points 3 are near OB associations of N11,3 are in supernovae field & one is in HII region of 30 Doradus region.
[edit] References
Cole et al. AJ 118 220[1]
1) Draine,B.T.,2003, ARA&A,41,241.
2) Schlegel,D.J.,Finkbeiner,D.P.,& Davis,M.,1998,APJ,500,538.
3) Hyland,A.R.,Straw,S.,Jones,T.J.,&Gatley,I.,1992,MNRAS 257,391.
4) Rubio,M.,Barba,R.H.,Walborn,N.R.,Probst,R.G.,Garcia,J.,& Roth,M.R.,1998,AJ 116,1708.
